ML20206N576
| ML20206N576 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 05/13/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20206N570 | List: |
| References | |
| NUDOCS 9905170273 | |
| Download: ML20206N576 (3) | |
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UNITED STATES j
j NUCLEAR REGULATORY COMMISSION i
g WASHINGTON, D.C. 20066 0001 4.,...../
j SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS.m AND m TO FACILITY OPERATING LICENSE NOS. NPF-39 AND NPF-85 PECO ENERGY COMPANY LIMERICK GENERATING STATION. UNITS 1 AND 2 DOCKET NOS. 50-352 AND 50-353
1.0 INTRODUCTION
By letter dated October 30,1998, as supplemented February 22,1999, the PECO Energy,
Company (the licen.see) submitted a request for changes to the Limerick Generating Station, Units 1 and 2, Technical Specifications (TSs). The requested changes would revise the overvoltage (OV), undervoltage (UV), and underfrequency (UF) allowable values associated with the reactor protection system monitoring channels and add supporting details to the Technical Specification Bases 3/4.8.4. The February 22,1999, letter provided clarifying information that did not change the initial proposed no significant hazards consideration
- determination.
2.0' DISCUSSION The Reactor Protection System (RPS) Monitoring System protects the loads connected to the RPS bus from unacceptable voltage and frequency conditions. The system isolates the RPS bus from the RPS/UPS (uninterrupted power supply) inverter or an attemate power supply in the event of overvoltage, undervoltage, or underfrequency. The RPS buses power the RPS logic, scram solenoids, and valve isolation logic. The TS Surveillance Requirements
'4.8.4.3.b.1,4.8.4.3.b.2, and 4.8.4.3.b.3 list the OV, UV, and UF allowable values for the protective instrumentation for the RPS electric monitoring channels. During a revision to a calculation for an RPS Breaker Panel-RPS/UPS system bus relay settings, the licensee discovered a discrepancy between existing TS 4.8.4.3 and General Electric (GE) Design Specification 22A3083AB. By letter dated October 30,1998, as supplemented February 22, 1999, the licensee requested approval of the TS change to revise the allowable values listed in TS 4.8.4.3 and add supporting details in the TS Bases Section 3/4.8.4.
3.0 EVALUATION The proposed change corrects a discrepancy between the GE Design Specification for power supply monitoring relays and the existing TS allowable values listed in TS 4.8.4.3. Currently,.
TS 4.8.4.3 identifies the required values for the RPS electric monitoring relays; OV, UV, and UF. The licensee's investigation into the licensing basis identified nominal values of +/- 10% of 120 Vac and -5% of 60 Hz for the allowable values. These values are included in NUREG-0123, from which the TSs for Limerick were developed.
9905170273 990513 PDR ADOCK 05000352 p.
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_ The existirig TS values are as follows:
Overvoltage s 132Vac Undervoltage a.10gVac
' Underfrequency a 57Hz-The proposed TS values are as follows:
Overvoltage's 127.5Vac
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Undervoltage a 110.7Vac Underfrequency E 57.05Hz
' The GE Design Specification 22A3083AB provides the criteria for setting the respective relays to ensure critical RPS components are not subjected to abnormal voltages and frequency.
Part of this methodology is to include voltage drops between the relays and the components.
This guidance was not previously included in the calculation of allowable values for OV and UV. When the voltage drops are added into the current TS allowable values for OV and UV relays, the resultant voltages were not adequate to protect the RPS electrical components.
The allowable value is the maximum (or minimum) value at which the instrument may be set,.
which will assure its actuation prior to a parameter exceeding the design limit (DL). OV DL and UV DL are determined based on the requirements of GE Spec 22A3083, which include the voltage drop's. OV DL and UV DL thus calculated are s 128.5Vac for OV and 2109.8Vac for
- UV. The new allowable values are determined by including relay accuracy (RA) and calibration accuracy (CA) in their calculations. CA refers to errors introduced by the inaccuracies of calibrating equipment and the allowances for error introduced by the calibration procedures.
After subtracting CA and RA values (0.87V) from OV DL (128.5V), the allowable value for OV is s 127.6Vac. Similarly, after adding CA and RA values (0.86V) to UV DL (109.8V), the allowable value for UV is a 110.7Vac. DL for UF is 57 HZ (60 Hz - 5%). Similarly, after adding CA and RA values (0.05 Hz) to UF DL (57 HZ), the allowable value for UF is a 57.05 HZ. The allowable value is listed in the TS. The proposed changes bring the TSs into agreement with plant design specifications and will ensure that adequate protection is provided for RPS components.
The proposed change also includes an addition to the TS Bases Section 3/4.8.4 providing details as to how the allowable values are derived and the basis for the instrument settings.
Summary The staff concludes the following:
1.
The proposed TS change provides more conservative allowable values for OV, UV, and UF.
2.
The proposed change brings the TSs into agreement with GE Design Specifications and will assure that adequate protection continues to be provided for the RPS components.
,e,
Based on the NRC staff review of the licensee's submittals, the staff finds the proposed ichanges to the TS and the associated Bases acceptable.
4.0 STATE CONSULTATION
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in accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendments. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to installation or use of a facility-component located within the restricted area as defined in 10 CFR Part 20 and change the -
surveillance requirements. The NRC staff has determined that the amendments involve no
- significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (63 FR 64120). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR i
51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
6.0 CONCLUSION
The Commission has concluded, based on the' considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
' Principal Contributors: N. Trehan B. Buckley Date:. Ity 13,1999 L
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